A method is presented to evaluate quantitatively the operation of the invertron, a recently developed device for measuring directly the lifetimes of quantized systems lying in the nanosecond range. The device consists of two electrodes in cylindrical geometry, the inner positive‐grid electrode being 45% transparent to electrons while the outer is an rf‐heated cathode.

Using the London theory we investigate the inductance of a system consisting of a long straight conductor of uniform cross section situated parallel to a nearby superconducting plate. Explicit formulas are derived for the particular cases of conductors having cylindrical, rectangular, and thin‐film cross sections and the limitations of the theory are discussed. The conclusions indicate that measurements of the inductance of such a system can be used to determine the penetration depth of a superconductor.

The eddy‐current method for measuringelectrical resistivity is extended to situations in which the resistivity is anisotropic. It is shown that in most cases of interest in practice, one can obtain the full resistivitytensor from eddy‐current measurements.

Measurements of internal friction and Young's modulus between −210° and 700°C have been carried out at frequencies 130–185 kHz on U4O9single crystals. Two pronounced internal friction peaks were observed, one at 60° and the other at −175°C. The peak at the higher temperature seems to be due to a phase transition of U4O9. The factors affecting the peak suggest that it is not caused by a relaxation process. It is suggested that some cooperative movements of interstitial oxygen ions in some lattice planes cause such a transition. The peak at the lower temperature is due to a relaxation effect. A rough calculation of the activation energy gave 0.034 eV. In addition, the results of the electrical conductivitymeasurements at low temperatures (25°–−160°C) gave the activation energy of 0.057 eV, in an approximate agreement with the one derived from the internal frictionmeasurements. This indicates that the relaxation process involves activated charge transfer between U5+ and U4+ ions (hopping motion of electronic holes). It is tentatively proposed that stress‐induced ordering of a defect complex involving U5+ ion and some oxygen ion(s), which produces a 〈111〉 elastic distortion in the lattice, gives rise to the relaxation effect.

The long‐range interaction between localized defects in an infinite elastically isotropic solid is derived. It is shown that when the defect has cubic symmetry the interaction energy is proportional to the inverse fifth power of the separation, in agreement with the result previously obtained from discrete lattice theory. The difference in magnitude of the interaction derived by the two methods is attributed to phonon dispersion.

The generation of misfit dislocations has been investigated on epitaxialsilicon wafers with boron‐doped substrates, as a function of the film thickness and the misfit resulting from the difference in lattice parameters between the film and the substrate. Critical values of the film thickness hc and of the misfit fc required to form misfit dislocations were found to be hc=2.4–‐2.9 μ for the interfacial misfit of 0.019% and fc=0.003–0.006% for relatively large film thickness, where the interfacial energy approaches that of infinitely thick film. These results were analyzed in terms of van der Merwe's theory and a good agreement was found between the experiment and the theory. The density of misfit dislocations was observed to increase with the interfacial misfit or with the film thickness. The relation between bending of the specimens associated with the misfit and the film thickness was studied. Some properties of misfit dislocations are described.

An analysis of the behavior of concentric circular dislocation glide loops of opposite sign lying on parallel slip planes has been performed by numerical methods. At large loop radii, a critical stress exists above which the loops may pass one another. This stress decreases as the slip plane spacing between the loops increases or as the loop radii increase. Below the critical passing stress the loops become coupled. In the absence of a lattice friction stress the coupled loops continuously shrink and ultimately vanish. If, on the other hand, such a friction stress exists, there also exists a critical loop radius above which the coupled loops remain permanently stuck within the crystal.

A mathematical analysis for the accumulation of tracer as diffused through a thin metallic slab by grain‐boundary diffusion is presented. Boundary conditions on the side where the tracer is deposited consist of a small depletable source, and the grain‐boundary concentration is enhanced by surface diffusion. Due to the mathematical difficulty associated with boundary conditions for combined grain‐boundary and surface diffusion, two cases are studied: No accelerated surface diffusion and infinite surface diffusivity along with finite grain‐boundary diffusivity. The difference between the accumulated tracer for the two cases is similar to the contribution from lattice diffusion only. Thus, for a relatively short diffusion time, grain‐boundary diffusion analyses without surface diffusion complications are correct.

Results are presented of a study of the (normalized) complex dielectric coefficient, and related parameters, of unidirectionally frozen artificial sea ice having salinities from 4 to 20‰. The frequency dispersion was investigated between 20 Hz and 100 MHz at temperatures from −35° to −12.5°C. An unusual measurement cell, which becomes incorporated into the ice as it forms, is described and justification offered for its use. The frequency dispersion of the real part of the dielectric coefficient may be considered in three parts. Large values (105 to 106 at −15°C, and 103 to 104 at −35°C) were observed at 20 Hz, falling slightly more rapidly than (frequency)−1 up to 5 kHz. Between 5 and 500 KHz most curves exhibited a distinct downward concavity (which was more prominent at lower temperatures), values dropping from between 103 and 104 to the order of 102 over this range. At higher frequencies the rate of decrease was smaller, values of 10 or less being observed at 100 MHz. Loss factors (values at 20 Hz: 106 to 107 at −15°C, and 104 to 105 at −35°C) in most cases decreased approximately as (frequency)−1 over most of the frequency range. Loss tangents, which were slightly larger at higher temperatures, were of order 10 below 1 MHz, dropping to less than 1 above 10 MHz. The curves for this parameter exhibited two temperature‐dependent maxima. The electrical properties changed most rapidly with temperatures near −23°C, the NaCl deposition temperature.

The temperature and pressure dependence of the dielectric constant ε′ of CdF2 has been measured for T=4°−300° K (at atmospheric pressure) and P=1–2000 bar (at room temperature). The frequency dependence of the real and imaginary parts (ε′ and ε″) has been investigated up to 100 MHz.

The present theoretical analysis permits simple, rigorous calculation of the equilibrium properties of state of a ferroelectric possessing a first‐order phase transition. The positive critical field in BaTiO3 is approximately 9×105 V/m. Experimental observation of the critical point should result in a better value for the temperature dependence of the fifth‐order thermodynamic coefficient ζ.

The stability against low‐frequency, electrostatic, flute‐like oscillations of a tenuous, hot, plane layer of charged particles embedded in a uniform and constant magnetic field is considered. It is shown that finite Larmor radius effects do not modify essentially the diocotron modes. It is also shown that a layer of particles whose guiding centers are located on a thin (with respect to the thickness of the layer) sheet around the midplane of the layer, is unstable: more precisely it has, for long (with respect to the thickness of the layer) waves, the same dispersion relation which holds for the diocotron modes. This strongly supports the conclusion that the diocotron instability of a charged, tenuous, plane layer is essentially independent from its kinetic structure.

The storage of protons and 3He ions in a circular storage‐ring ion trap with background gas collision‐limited loss time constants up to 8 min long under ultrahigh‐vacuum conditions is described. Storage‐ring traps were derived from the linear quadrupole rf mass filter by shaping the electrodes into circular and racetrack configurations. Operation of the traps with a trapping rf frequency Ω large compared to the secular ion oscillation frequency ω inhibited ion loss due to nonlinearities in the trapping fields. Long‐term ion storage in such traps may prove useful for radio‐frequency ion spectroscopic purposes.

Electret theory is briefly summarized and discussed. The electret strength as usually measured is shown to depend on the measuring method, the electret thickness, and the storage conditions. This is caused by charge leakage and sparking. The maximum charge density as a function of electret thickness is calculated; the thicker the electret the lower the maximum charge density. Our electrets are thin (5 μm) polymer membranes, provided with evaporated goldelectrodes. They do not have to be stored in a short‐circuited condition.

Wave decay on glass surfaces at high temperatures is treated assuming glass to behave as a Newtonian viscous fluid in the high‐temperature region. To meet with different kinds of irregularities and various production techniques, two‐dimensional and axisymmetric waves with several boundary conditions are analyzed, each yielding the amplitude ratio at any instant in terms of the physical constants. Crude experiments are performed and found to agree fairly well with the theoretical results.

A rudimentary capillary‐type viscometer for measuringviscosities between 103 and 1010 poise at high pressures is described. Measurements are reported on petroleum ether to 57 kbar where the viscosity is approximately 1010 poise and on a 1:1 mixture of n‐pentane‐isopentane to 54 kbar where the viscosity is approximately 106 poise. Measurement precision of the technique is a few percent, but uncertainty in absolute determination at maximum pressure is only within a factor of two. Viscous stresses are shown to decay exponentially with time even at the highest pressures, and no effects of residual stress are observed.

To study the anharmonic properties of Al at low temperatures, the pressure derivatives of the elastic constants have been measured from 77° to 300°K. The isothermal elastic constants are obtained as a function of pressure by a self‐consistent analysis of the ultrasonic data. The most probable values for the pressure derivatives are calculated from the results of six measurements of different combinations of the elastic constants. The pressure derivatives are found to be almost constant below ΘD/3 and increasing for higher temperatures. Using the quasiharmonic approximation, the Grüneisen constant γ is calculated from our results and found to be about 15% higher than the thermal γ in the temperature range studied. We have calculated the elastic γ for T≪ΘD from the extrapolated values of the pressure derivatives. It turns out to be 2.51, a value in excellent agreement with the low‐temperature lattice thermal γ. The equation of state in the Murnaghan form and in a series expansion of the volume change in terms of pressure is discussed for Al. A good agreement can be obtained between the ultrasonic and the static and shock compression results if the latter data are analyzed according to the Murnaghan equation of state.

The feasibility of laser‐machining quartz crystal resonators for frequency and inter‐resonator coupling adjustment has been demonstrated. The inter‐resonator coupling has been adjusted by altering the geometry of the electrode array. The frequency has been adjusted by vaporizing material to form an array of holes on the electrode surface. The results indicate that extremely fine adjustments of inter‐resonator coupling and resonator frequency can be achieved. Frequency adjustments greater than one part in 108 have been demonstrated. No degradation of the crystal unit electrical parameters could be detected as a result of the machining process. Furthermore, laser trimming lends itself to automated processing without the need for elaborate vacuum equipment as is presently required with some adjustment techniques. Laser trimming also appears to be ideally suited for adjustment of high‐frequency resonators where fine tolerances are required.

A number of high‐melting‐point rare‐earth compounds have been examined for superconductivity. In this work LaC2, LuC2, and YGa2 were found to be superconductors, but Y3C, LaGa2, La5Sn3, and Y5Sn3 did not exhibit superconductivity in tests down to 1.4 K.

The avalanchebreakdown of reverse biased p‐njunctions in GaP is investigated. Electrical studies comprise measurements of I‐V characteristics,breakdown field, and electrical noise as functions of temperature. The high‐temperature light emission from microplasmas consists of a broad emission band with a maximum, near 1.7–1.8 eV, but otherwise with no structure. Its shape is analyzed in detail and discussed in view of theoretical models. The quantum efficiency of this band is independent of the lattice temperature. Neither the spectral shape nor the quantum efficiency of the emission band appear to be related to details of the energy‐band structure. At low temperatures, additional emission lines caused by minority carrier recombination outside the breakdown region are observed.